Optical communication systems transfer signals from a transmitter (TX) of one system to a receiver (RX) of another system. In general, optical signals can be transmitted through an optical fiber at relatively high data rates and low signal attenuation therefore making such data transmission suitable for, e.g., telephony, Internet, and cable television.
FIG. 1 schematically illustrates a conventional optical communication system 10. A source of light 12 (e.g., a laser, a light emitting diode, etc.) emits light 14 that is directed to one end of an optical fiber 16 via a transmitter (not shown). Due to relatively low signal attenuation, the optical fiber can transfer signals over long distances, e.g., tens or hundreds of kilometers. At the other end of the optical fiber 16, the transferred light 18 is received by an RX 20.
Typically, the RX 20 is tuned to receive the optical signals at a particular incoming wavelength, e.g., the wavelength λ0 of the source of light 12. However, in some practical applications the wavelength at which light is emitted by the source of light varies, e.g., because of temperature variations of the source of light 12. For example, the source of light 12 may emit at a wavelength λ0 when at temperature T0, and at a wavelength λ1 when at temperature T1. The difference between the expected wavelength λ0 and the received wavelength λ1 at the RX can degrade performance of the optical communication system, especially for telecommunication equipment that should operate reliably within a relatively wide temperature range of 0° C.-80° C. Therefore, some conventional technologies use specialized lasers capable of producing highly stable wavelengths even over a relatively wide range of temperatures. However, such specialized telecommunication lasers may be too expensive for lower cost applications, e.g., data center applications.
Other conventional technologies rely on the calibration of the RX to better match the wavelength of the incoming light to a peak sensitivity of the RX. However, calibration causes downtime, therefore resulting in reduced availability of these conventional systems. Accordingly, there remains a need for relatively low cost and high availability systems having good sensitivity to the wavelengths emitted by a light source over a range of temperatures.